Most people have at least one loved one affected by cancer. This can sometimes create an impression that cancer runs in families or is inherited. More likely, though, cancer occurs by chance and may also be linked to a combination of certain genetic and lifestyle risk factors shared within a family. A small number of cancer cases (approximately 5-10 percent of all cancers) are directly caused by a single genetic change (or mutation) that is passed down from generation to generation leading to significantly higher cancer risk compared to the general population.
All cancers are genetic, meaning they occur after genes undergo mutations. Genes are strands of DNA that provide instructions for all cellular behavior, including when a cell should grow and divide as well as the appropriate time for it to die. Faulty instructions can cause cells to multiply uncontrollably and live longer than they should. The resulting accumulation of excess cells can bind together and form tumors which sometimes become malignant. While some people are born with genetic mutations that increase their lifetime risk for developing cancer (i.e., inherited cancer risk), the vast majority of genetic mutations are caused by environmental and lifestyle factors and sometimes occur for no apparent reason.
Genetic testing in an oncology setting is a valuable tool that a healthcare provider can use to better understand a patient’s unique risk for cancer as well refine their cancer treatment. Depending on the type of testing being ordered, a sample of blood, saliva or tumor tissue may be obtained for analysis.. Results of testing can provide important clues about:
When Testing for Inherited Cancer (mutations an individual was born with)
- A patient’s risk for developing certain cancers
- Cancer risk among a patient’s relatives
- Strategies for early detection and/or prevention of cancers
When Testing for Mutations Confined to the Tumor (tumor testing)
- How aggressive a cancer may be
- How a tumor may respond to certain treatments
- Which treatments may be most appropriate for a patient
While genetic testing is generally safe, results are highly accurate and the cost barrier is generally minimized for most patients, speaking to a healthcare provider about the option of genetic testing is an important first step in making a decision that is right for you. A genetic counselor is a masters-trained healthcare provider who can help to explain the purpose of testing and the implications of the results for both the patient and their family prior to testing. It’s also important to understand that federal law prohibits employers and health insurance companies from using the results of genetic testing for discriminatory purposes, although these laws do not provide protections against discrimination for supplemental types of insurance (i.e., life, long-term care, disability).
With all of that said, a decision to undergo genetic testing is voluntary and highly personal. Every individual is encouraged to make the decision about testing that is best for them and their family. In addition to genetic testing, there are many other pieces of information used to receive tailored cancer treatment.
If you’d like to discuss genetic testing with a cancer specialist at Moffitt Cancer Center, you can request an appointment by calling 1-888-MOFFITT or completing a new patient registration form online. You do not need a referral to meet with our expert oncologists, who can develop an individualized screening and treatment plan for you.